THE ADSORPTION OF SURFACE-ACTIVE COMPLEXES BETWEEN BETA-CASEIN, BETA-LACTOGLOBULIN AND IONIC SURFACTANTS AND THEIR SHEAR RHEOLOGICAL BEHAVIOR

The surface tension isotherms of beta-lactoglobulin and beta-casein in mixtures with sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB), respectively, strongly indicate the formation of surf ace-active complexes. These complexes saturate the adsorption layer at concentrations lower than the saturation concentrations of the indivi dual components. Further increases of surfactant concentration lead to the formation of less-surface-active complexes which compete with fre e surfactant molecules and are replaced at sufficiently high surfactan t concentrations. The surface shear viscosity is progressively decreas ed by the addition of the surfactants.